<!DOCTYPE html>
<html>
  <head>
    <title>mphantom</title>
    <meta charset="utf-8"/>
  </head>
  <body>

    <!-- Test different kinds of content inside <mphantom>. -->
    <p><math>
      <mrow style="visibility: hidden">
        <msqrt>
          <mfrac>
            <mn>1</mn>
            <mi>x</mi>
          </mfrac>
        </msqrt>
        <mo>+</mo>
        <menclose notation="box updiagonalstrike">
          <mover>
            <mspace width="3em" height="1em" mathbackground="red"/>
            <mo>‾</mo>
          </mover>
        </menclose>
      </mrow>
    </math></p>

  </body>
</html>
